1. Field of the Invention
The invention is relative to a knife ring machining tool for machining or cutting chips and shavings. Such a machining tool is known, e.g., from DE 32 47 629 C1.
2. Description of the Related Art
Such a machining tool is designed as follows: It comprises a knife ring with a plurality of knife packets. Each knife packet comprises a knife that faces inward with its cutting edge and is inclined against the radial direction. The knife ring surrounds a rotor arranged coaxially with the knife ring. The rotor comprises a plurality of rotor blades. Each rotor blade carries a strip-shaped cleaving knife arranged parallel to the shaft and extending over the width of the rotor. Chips are supplied to the rotor, substantially in the axial direction, which the rotor casts outwardly against the knife packet. These cleaving knives cooperate thereby with the knives of the knife ring in that they break the chips down into fine shavings.
The radially outside dimension of the cleaving knives, the so-called flight circle, is a very critical dimension. It must be precisely adjusted and also maintained in this adjustment. It must be prevented, in any case, that the cleaving knives extend too far outward radially since they otherwise collide with the knives of the knife ring.
The cleaving knives are fastened to the rotor blades by screws. The cleaving knives comprise oblong holes extending in radial direction and through which the screws are run. These oblong holes are necessary because the cleaving knives wear down in the course of time and because a certain radial adjustment toward the outside is accordingly necessary after a certain operating time. The connection with the fastening screws can therefore only be a non-positive one. However, this is critical because a slow radially outward travel or creep of the cleaving knives can occur due to the high centrifugal forces.
The invention has the problem of designing a knife ring machining tool, especially its rotor, in such a manner that the radial position of the cleaving knives is reliably maintained.
The inventors have found a solution that is as simple as it is reliable. Each screw connection is provided, in accordance with the invention, with a wedge-shaped element through which the fastening screw is run and that tapers, viewed in a section vertical to the axis, in radial direction from the outside to the inside in a wedge shape.
This has the following effect: Centrifugal forces occur during operation, as stated. These forces act on the cleaving knives but also on the wedge elements. Both of them have a tendency to travel outward; however, an even more forceful tightening of the screw connection occurs even at a minimal radially outward travel on account of the wedge effect of the wedge element. This prevents the individual cleaving knife from executing an appreciable radially outward traveling motion.